Моделирование уравнений проекционного осциллографирования на машине "ЭМУ-10"

The passive-alignment-packaging technique presented in this work provides a method for mounting tolerance-insensitive optical components e.g. non-linear crystals by means of mechanical stops. The requested tolerances for the angle deviation are ±100 µrad and for the position tolerance ±100 µm. Only the angle tolerances were investigated, because they are more critical. The measurements were carried out with an autocollimator. Fused silica components were used for test series. A solder investigation was carried out. Different types of solder were tested. Due to good solderability on air and low induced stress in optical components, Sn based solders were indicated as the most suitable solders. In addition several concepts of reflow soldering configuration were realized. In the first iteration a system with only the alignment of the yaw angle was implemented. The deviation for all materials after the thermal and mechanical cycling was within the tolerances. The solderability of BBO and LBO crystals was investigated and concepts for mounting were developed

Influence of suture technique and suture material selection on the mechanics of end-to-end and end-to-side anastomoses

AbstractExperiments were performed in dogs to evaluate the mechanics of 26 end-to-end and 42 end-to-side artery-vein graft anastomoses constructed with continuous polypropylene sutures (Surgilene; Davis & Geck, Division of American Cyanamid Co., Danbury, Conn.), continuous polybutester sutures (Novafil; Davis & Geck), and interrupted stitches with either suture material. After construction, the grafts and adjoining arteries were excised, mounted in vitro at in situ length, filled with a dilute barium sulfate suspension, and pressurized in 25 mm Hg steps up to 200 mm Hg. Radiographs were obtained at each pressure. The computed cross-sectional areas of the anastomoses were compared with those of the native arteries at corresponding pressures. Results showed that for the end-to-end anastomoses at 100 mm Hg the cross-sectional areas of the continuous Surgilene anastomoses were 70% of the native artery cross-sectional areas, the cross-sectional areas of the continuous Novafil anastomoses were 90% of the native artery cross-sectional areas, and the cross-sectional areas of the interrupted anastomoses were 107% of the native artery cross-sectional areas ( p < 0.05). At physiologic pressures, there were no differences in compliance among the three types of anastomosis. These data suggest that when constructing an end-to-end anastomosis in a small vessel, one should use an interrupted suture line or possibly continuous polybutester suture. Forty-two end-to-side anastomoses demonstrated no differences in cross-sectional areas or compliance for the three suture techniques. This suggests that, unlike with end-to-end anastomoses, when constructing an end-to-side anastomosis in patients any of the three suture techniques may be acceptable. (J THORAC CARDIOVASC SURG 1996;111:1063-72

Anaerobic degradation of p-xylene by a sulfate-reducing enrichment culture.

A strictly anaerobic enrichment culture was obtained with p-xylene as organic substrate and sulfate as electron acceptor from an aquifer at a former gasworks plant contaminated with aromatic hydrocarbons. p-Xylene was completely oxidized to CO(2). The enrichment culture depended on Fe(II) in the medium as a scavenger of the produced sulfide. 4-Methylbenzylsuccinic acid and 4-methylphenylitaconic acid were identified in supernatants of cultures indicating that degradation of p-xylene was initiated by fumarate addition to one of the methyl groups. Therefore, p-xylene degradation probably proceeds analogously to toluene degradation by Thauera aromatica or anaerobic degradation pathways for o- and m-xylene

Degradation of o-xylene and m-xylene by a novel sulfate-reducer belonging to the genus Desulfotomaculum.

A strictly anaerobic bacterium, strain OX39, was isolated with o-xylene as organic substrate and sulfate as electron acceptor from an aquifer at a former gasworks plant contaminated with aromatic hydrocarbons. Apart from o-xylene, strain OX39 grew on m-xylene and toluene and all three substrates were oxidized completely to CO2. Induction experiments indicated that o-xylene, m-xylene, and toluene degradation were initiated by different specific enzymes. Methylbenzylsuccinate was identified in supernatants of cultures grown on o-xylene and m-xylene, and benzylsuccinate was detected in supernatants of toluene-grown cells, thus indicating that degradation was initiated in all three cases by fumarate addition to the methyl group. Strain OX39 was sensitive towards sulfide and depended on Fe(II) in the medium as a scavenger of the produced sulfide. Analysis of the PCR-amplified 16S rRNA gene revealed that strain OX39 affiliates with the gram-positive endospore-forming sulfate reducers of the genus Desulfotomaculum and is the first hydrocarbonoxidizing bacterium in this genus

Intrinsic biodegradation potential of aromatic hydrocarbons in an alluvial aquifer - Potentials and limits of signature metabolite analysis and two stable isotope-based techniques

Three independent techniques were used to assess the biodegradation of monoaromatic hydrocarbons and low-molecular weight polyaromatic hydrocarbons in the alluvial aquifer at the site of a former cokery (Flémalle, Belgium). Firstly, a stable carbon isotope-based field method allowed quantifying biodegradation of monoaromatic compounds in situ and confirmed the degradation of naphthalene. No evidence could be deduced from stable isotope shifts for the intrinsic biodegradation of larger molecules such as methylnaphthalenes or acenaphthene. Secondly, using signature metabolite analysis, various intermediates of the anaerobic degradation of (poly-) aromatic and heterocyclic compounds were identified. The discovery of a novel metabolite of acenaphthene in groundwater samples permitted deeper insights into the anaerobic biodegradation of almost persistent environmental contaminants. A third method, microcosm incubations with 13C-labeled compounds under in situ-like conditions, complemented techniques one and two by providing quantitative information on contaminant biodegradation independent of molecule size and sorption properties. Thanks to stable isotope labels, the sensitivity of this method was much higher compared to classical microcosm studies. The 13C-microcosm approach allowed the determination of first-order rate constants for 13C-labeled benzene, naphthalene, or acenaphthene even in cases when degradation activities were only small. The plausibility of the third method was checked by comparing 13C-microcosm-derived rates to field-derived rates of the first approach. Further advantage of the use of 13C-labels in microcosms is that novel metabolites can be linked more easily to specific mother compounds even in complex systems. This was achieved using alluvial sediments where 13C-acenaphthyl methylsuccinate was identified as transformation product of the anaerobic degradation of acenaphthene